Change example to frontend/backend
Change example to frontend/backend

Make it clear that a PuppetMaster is required for most nodes. Vagrant will
use the `puppet apply` provisioner using shared folders.

alphagov/govuk-puppet,alphagov/govuk-puppet,alphagov/govuk-puppet,alphagov/govuk-puppet,alphagov/govuk-puppet,alphagov/govuk-puppet